Package can be install from CDROM, Network i.e. NFS or downloading from Internet and then add it to system, or from existing location such as /var/spool/pkg directory if frequently required packages are copied to this location.

Solaris: Adding package from CDROM
1) Mount cdrom

2) To add or install GNU tar package from Solaris CD use command
# pkgadd -d /cdrom/cdrom0/Solaris_9/Product SUNWgtar

Where,
-d /cdrom/cdrom0/Solaris_9/Product: Specify package directory
SUNWgtar: Package name

Solaris: Adding packages to spool directory and then install them
1) Copy package to /var/spool/pkg directory first:
# pkgadd -d /cdrom/cdrom0/Solaris_9/Product -s /var/spool/pkg SUNWgtar
Transferring package instance

Where,
-d /cdrom/cdrom0/Solaris_9/Product: Specify package directory
-s /var/spool/pkg : Directory in which package will get stored
SUNWgtar: Package name

2) Install the packages copied to spool directory
# pkgadd SUNWgtar

Solaris: Install downloaded package
1) If your package is in .bz2 format then first uncompress it using bunzip2 command:
# bunzip2 Packagname.bz2

2) Install package:
# pkgadd –d Packagname

Note .bz2 extension will automatically removed by first command.

For example if your package name is SFWqt.bz2
# buzip2 SFWqt.bz2
# pkgadd –d SFWqt